As digital technology has been greatly developed in recent years, digital broadcast, digital contents distribution by Internet, digital contents distribution and accumulation by DVD, hard disc and memory card are becoming very popular. Since digital data are used in these media, it is possible to copy the data without deterioration in quality. However, it is important to realize security for preventing such unjust copying from the viewpoint of copyright protection. For realizing the security, revocation information that is a so-called black list of unjust apparatuses has to be issued when the apparatus is found to be an unjust apparatus from the viewpoint of copyright protection. And, it is necessary for the apparatus which can be connected to an unjust apparatus to have the revocation information and to prevent unfair access to digital contents.
FIG. 31 is an example of conventional system for renewing of revocation information, and the configuration of the system is shown in FIG. 25. Such a configuration is disclosed in Japanese Laid-Open Patent 2001-166996.
Contents sales system 3001 is an automatic vending machine which electronically distributes musical contents via a transmission network such as broadcast and Internet. Electric music distributor (EMD in FIG. 31, and also, EMD in later description) 3002 is a music server or music broadcasting station. Revocation information issuing authority 3003 issues revocation information. Revocation information storage section 3005 receives revocation information issued by revocation information issuing authority 3003. Music data storage section 3006 stores music data. License storage section 3007 stores a key for decoding coded contents. EMD I/F 3008 is an interface for receiving coded contents. PD I/F 3009 is an interface for connection to playback device (PD) 3012. Media I/F 3010 is a card slot of PCMCIA for mounting recording media 3014. Recording media 3014 is a portable media (PM). Playback device 3012 comprises recording media 3013. User I/F 3011 is an interface to be operated by user. Security contents server 3004 is a server, and the information is delivered and received between EMD I/F 3008, revocation information storage section 3005, music data storage section 3006, license storage section 3007, media I/F 3010, user I/F 3011, and PD I/F 3009.